1. Technical Field
The present invention relates to a light source unit and a projector.
2. Related Art
In the related art, a projector configured to modulate light emitted from a light source unit in accordance with image information and project the modulated light onto a projection surface such as a screen is known. In the light source unit, a discharging type light source such as an extra high pressure mercury lamp is employed. The light source generates heat in association with a light emission, and the temperature of an upper portion thereof is increased to a temperature higher than the temperature of a lower portion thereof due to an influence of heat convection. When a high-temperature state of the light source continues, the light source is subjected to loss of clarity, is blackened and hence is deteriorated with an increase in a temperature difference between the upper portion and the lower portion.
The projector is used in a standing position in which the projector is placed on a desk or on a floor, and in a suspending position which is a position to be installed upside down, that is, a position inverted from the standing position, on a ceiling or the like. Therefore, when a flow channel configured to cool the light source unit is fixed corresponding to either one of the standing position or the suspending position, there arises a problem that the light source unit cannot be cooled adequately in the other position.
Therefore, a technology configured to cool the light source efficiently in both of the standing position and the suspending position is proposed (for example, see JP-A-2012-27171).
The light source unit described in JP-A-2012-27171 includes a light-emitting tube, a reflector, and a holding unit configured to hold the reflector.
The holding unit includes an intake port 32, a partitioning portion provided between the intake port 32 and the light-emitting tube, a pair of flow channels provided so as to be branched to an upper side and a lower side of the light-emitting tube, and a shutter configured to rotate under its own weight. The intake port 32 is formed so as to introduce cooling air in a direction substantially orthogonal to a lighting optical axis, and the partitioning portion is provided with an opening 38. The shutter is formed so as to rotate about an axis of rotation extending substantially parallel to the lighting optical axis and close the lower flow channel, and is provided with an opening 42 that overlaps with the opening 38 of the partitioning portion on the axis of rotation side.
The light source unit described in JP-A-2012-27171 is configured to allow the cooling air introduced from the intake port 32 to flow through the upper flow channel, which is one of the pair of flow channels not closed by the shutter, toward the light-emitting tube. Part of the cooling air introduced from the intake port 32 is directed to flow along the light-emitting tube via the openings 38 and 42. Therefore, the light source unit described in JP-A-2012-27171 is configured to cool the light-emitting tube from above and from the sides in both positions, that is, the standing position and the suspending position simultaneously.
However, the light source unit described in JP-A-2012-27171 is configured to close one of the flow channels with the shutter, the light source unit is liable to be deteriorated due to lack of the cooling air to a lower part of the light-emitting tube or a high temperature of a part of the holding unit which defines the flow channel. Since the intake port 32 is formed so as to introduce the cooling air in the direction substantially orthogonal to the lighting optical axis, a space in which a fan that sends the cooling air to the intake port 32 is placed is increased in size, so that an apparatus having the light source unit is increased in size correspondingly. Since the intake port 32, the openings 38 and 42, and a distal end of the light-emitting tube are arranged so as to be positioned in a line, there is a problem that light is liable to leak to the outside of the light source unit.